Conventionally, microelectromechanical systems (MEMS) pressure sensors can comprise a MEMS chip attached to a substrate. These MEMS pressure sensors are generally formed with a rigid membrane separating a sealed cavity and an atmosphere. A pressure difference between the sealed cavity and the atmosphere cause a deformation of the membrane. Typically, the membrane separates the sealed cavity from the atmosphere and an absolute position of the membrane is determined. In conventional applications, the absolute position of the membrane is used to determine the atmospheric pressure. Determining the deformation of the membrane can include determining a change in capacitance, resonant frequency, and/or embedded resistance.
However, characteristics, such as sensitivity, frequency response, accuracy etc., of such conventional MEMS pressure sensors are limited by the MEMS device's design and the physical constraints imposed on the geometry of the package. Further, determining the absolute position can be problematic for several reasons, including potential damage to packaging, alteration of packaging due to temperature, frequent need for recalibration, and the like. Such systems can also suffer from false signals in offset or sensitivity induced by stress experienced by the packaging. These systems are also limited in the maximum pressure that they are able to sense due to, for instance, the mechanical strength of the membrane. Damage to the sealed cavity or packaging can further result in conventional pressure sensors becoming defective, unreliable, and/or unusable. Adding to the limitations of conventional pressure sensors is the difficulty of measuring small variations of atmospheric pressure against the large values of atmospheric pressure.
It is thus desired to provide MEMS pressure sensors that improve upon these and various other deficiencies. The above-described deficiencies of conventional MEMS pressure sensors are merely intended to provide an overview of some of the problems of conventional implementations, and are not intended to be exhaustive. Other problems with conventional implementations, techniques, and corresponding benefits of the various aspects described herein may become apparent upon review of the following description.